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February 2009

February 27, 2009

Landfilled food waste can generate significant amounts of methane through anerobic decomposition. In a wet boreal/temperate climate zone, typical methane emissions are about 1.4 Kg CO2e per Kg of wet food waste (based on IPCC guidelines and 100-year assessment period). To put this in context, most fruits and vegetables have embodied carbon emissions of less than 0.7 Kg of CO2e per Kg of product at the farm gate (with some exceptions such as greenhouse production). Thus, landfilling has at least twice the impact as the original production. If we produce 1 Kg of some fruit/vegetable at this carbon emission rate and then throw away 20% of that into a landfill without methane capture, we are essentially increasing the carbon footprint of the product by 40%. On the other hand, composting generates little or no methane (less than 1% to a few percent of the initial carbon content is released as methane), and the biogenic CO2 from composting is not counted toward global warming.

Landfills are the largest methane source in the US (see EPA). Among degradable organic matter in landfills, food waste decomposes faster than anything else with more of the methane emissions occurring earlier in the 100-year period, which means higher global warming potential. The EPA estimates that food waste diverted from landfills decreases GHG emissions by 0.82 tonnes of CO2e per tonne of food waste -- presumably accounting for some average percentage of methane capture in landfills (per this report).

In addition to increasing the average fuel economy of the auto fleet (through replacing enough clunkers with greener vehicles), we are going to need incentives to preserve the benefits of higher efficiency vehicles -- so that the fuel and cost savings are not used up in additional driving. One measure of this is the actual GHG emissions from the transportation sector. Beyond GHG emissions, there are other real costs to driving -- including wear and tear on the roads and other infrastructure, and the constant need to repave and widen the roads.

As the average fuel economy of the auto fleet improves, a tax on miles driven would be the next logical step in reducing both emissions and infrastructure costs. The tax would depend on miles driven, roads used, weight/size of the vehicle, etc., to fully account for the wear and tear and congestion caused by driving a particular vehicle a certain number of miles on specific routes. This can be done using GPS technology and might be the best way to fund future transport options.

February 09, 2009

Economist Alan Blinder suggested last year a Cash for Clunkers program in which the government would pay a premium to buy inefficient clunkers and take them off the road and resell them as scrap. Targeted at cars and light trucks that are over 15 years old (there are 75 million of these in the US, about 30% of the vehicles in use), this would cost about $4 billion per million cars based on an average purchase price of $3500, according to Blinder. Since most clunkers are owned by low-income people, this would transfer some purchasing power to them which they are likely to use quickly. So the idea is that this would also be an effective economic stimulus while reducing pollution. But a big potential problem with this proposal is that the cash paid for the clunker may be too little to help purchase a replacement vehicle that is significantly greener.

Although automakers are being pressured to produce more fuel-efficient vehicles, and there is some funding in the stimulus package for battery development and tax incentives for plug-in hybrids, there hasn't been a systematic approach to greening the auto fleet. It is clear that we know how to make vehicles that are significantly more efficient, but the price tag for a new green vehicle ($20,000 and up) makes it a challenge to replace enough of the older vehicles to really reduce GHG emissions.

A workable plan needs to target not all clunkers, but only those that are driven more than X miles per year, and must provide enough of a subsidy to help purchase a replacement vehicle that delivers at least Y miles per gallon based on GHG reduction goals. Plus some way to discourage the higher fuel efficiency from being used up in additional driving, so that GHG reduction goals are actually achievable. I'll be coming back with a bit more analysis soon.

February 06, 2009

A September 2008 report from the Political Economy Research Institute (University of Massachusetts) lays out the case for a rapid green economic recovery program. The report estimates that a two-year government investment of $100 billion in green buildup would create 2 million jobs -- four times as many jobs as investing the same amount in the oil industry and 300,000 more jobs than similar government spending (such as tax rebates) directed at increasing household consumption. Nearly half the new jobs would be in construction and manufacturing. The unemployment rates used in the report are from July 2008 and obsolete now, but the general conclusions are still important.

The initial version of the House stimulus bill appears to have about $54 billion allocated for renewable energy and overall energy efficiencies, and the list matches several of the key investment areas assumed in the above study. This does look like a decent down payment on a much-needed investment. There is uncertainty in all such estimates, to be sure, but if the green stimulus can come close to creating jobs at a cost of $50K per job while building a launch pad for the next crucial steps in green buildup, then it is an absolute win-win. Why didn't we just do this years ago and why aren't we investing more today?